German Patent Application DE 198 10 509 describes welding of dissimilar materials without prior tests. In DE 198 10 509, ultrasonic waves can be coupled into a welding material and recorded as a measurement signal based on interactions with a joining layer. The measurement signal can be stored in a measurement data memory. Subsequently, an evaluation unit can use the measurement signal to determine characteristic quantities for a welding process.
German Patent Application DE 43 21 874 A1 describes control and regulation of process parameters during ultrasonic welding of plastic parts. In DE 43 21 874 A1, the joining force can be measured during welding to monitor the energy applied to the joining point between the parts being welded.
European Patent Application EP 0 567 426 B1 describes a method for welding of plastic parts in which an oscillation amplitude of a sonotrode that is welding plastic parts can be reduced after a pre-determined time. As such, the sonotrode can work at a reduced oscillation amplitude during a remaining welding time. A control signal for reducing the oscillation amplitude can be triggered directly or indirectly based on the power transmitted to the parts being welded, as described, for example, in International Patent Application Publication WO 98/49009 and U.S. Pat. Nos. 5,435,863, 5,658,408, and 5,855,706.
International Patent Application Publication WO 02/098636 describes a method for welding of plastic parts in which an oscillation amplitude of a sonotrode can be reduced based on a pre-determined course for optimization of welding. Subsequently, a characteristic parameter of a part being welded can be measured, and the sonotrode can complete the welding process based on the value of the measured parameter with a constant oscillation amplitude.
German Patent Application DE 101 10 048 A1 describes checking connections made by ultrasonic wire bonding. In DE 101 10 048 A1, connections can be monitored on-line based on pre-determined stored master values and, based on monitoring the connections, conclusions can be drawn about the strength of the connections.